Tape wrapping machine



1366- 1966 K. MONTGOMERY TAPE WRAPPING MACHINE Filed Sept. 9, 1963 INVENTOR KE/VT MONTGOMERY BY%/ r/n/ {Wm ATTO NEY United States Patent 3,291,403 TAPE WRAPPING MACHINE Kent Montgomery, Bloomington, Minn., assignor to Gould-National Batteries, Inc., a corporation of Delaware Filed Sept. 9, 1963, Ser. No. 307,533 9 Claims. (Cl. 242-7) This invention relates generally to wrapping machines and in particular is directed toward improvements in the tensioning and guiding device for an automatic wrapping machine.

The preferred embodiment of this invention will hereafter be described in detail with respect to its use for wrapping glass fiber tape around electrode plates used in lead-acid storage batteries since it has provided particularly advantageous features when used for this purpose. From the detailed description, however, it will be seen that that the invention is not limited to that particular use and its advantages and features are equally realized when used according to the teachings of this invention for wrapping any of a variety'of articles.

In the highly competitive battery industry attention is constantly being directed toward improved products at reduced cost. It has been found, for example, that longevity of the electrode plates for use in lead-acid batteries can be enhanced with no substantial loss in capacity by wrapping the plates with a glass fiber tape to prevent any substantial loss of active material from the plate during normal use. By careful control of the uniformity of the wrapping and use of a suitable wrapping material, the wrap is made porous so as to maintain the normal capacity of the battery. Initially, wrapping of the plates was a hand operation which was time consuming and costly. Furthermore, the excessive handling of the plates during the wrapping operation resulted in active material being loosened from the plates. Additionally, control of the tension on the wrapping material as it was being wrapped was subject to human errors thereby resulting in non-uniformity of the wraps on the individual plates and on respective plates. Further since each plate was wrapped individually it was generally a time-consuming intermittent type of operation instead of a continuous operation necessary for mass production.

It is a general object of this invention to provide an improved device for wrapping articles with a tape or like material.

A more specific object of this invention is to provide a device for wrapping articles in a uniform manner.

Another object of this invention is to provide a device for maintaining accurate guidance and uniform tension on wrapping material as it is being wrapped around an article.

Still another object of this invention is to achieve the foregoing objects for articles of various and varying sizes and configurations.

Yet another object of this invention is to achieve the foregoing objects with an automatic wrapping machine.

A further object of this invention is to provide means in an automatic wrapping machine for preventing breakage of the wrapping material as it is being wrapped in the event of an increase in the tension of the wrapping material toward an unsafe limit.

A still further object of this invention is to provide means in an automatic wrapping machine for preventing the wrapping material from unreeling during the intermittent periods when no article is being wrapped.

Yet a further object of this invention is to provide means in an automatic wrapping machine for controlling the feed of the wrapping material in accordance with the demand.

These and other more specific objects and features will 3,291,403 Patented Dec. 13, 1966 ice be disclosed during the course of the following detailed description with reference to the accompanying drawings in which:

FIGURE 1 is a general schematic illustration of an embodiment of this invention;

FIG. 2 is a detailed illustration of an embodiment of this invention as utilized in the machine illustrated in FIG. 1, and

FIG. 3 illustrates the operation of the device of FIG. 2.

Referring now to FIG. 1, there is shown a pair of endless belts 10 and 12 which are driven in the direction respectively indicated by arrows 14 and 16 by any well known means, not shown, on their respective support structures shown generally at 18 and 20. It will be assumed, of course, that the belt velocities are synchronized generally by having a common driving system. A gap 22 between the endless belts generally defines the wrapping station. The articles to be wrapped, such as illustrated by battery plates 24, are continuously transported by the endless belts to and from the wrapping station. The articles to be wrapped are maintained in position at the wrapping station by a pair of idler rollers 26 and 28 journaled in their respective supporting members 18 and 20.

In a plane generally orthogonal to the plane defined by the transporting surfaces of the endless belts is an annular bobbin 30 on which is spooled multiple levels of wrapping material, such as glass fiber tape, as indicated at 32. The bobbin is driven rotationally about its axis in the direction of arrows 34 by appropriate driving means illustrated generally at 36 and 38. The speed of rotation is synchronized with the velocity of the endless belts in order to assure a uniform wrap in accordance with the speed at which the articles are transported through the wrapping station. Preferably, there would be included means for varying the relative speeds in order to selectively change the mesh or number of turns per inch of the wrap. The longitudinal extremities of the bobbin are defined by a pair of raised ridges or rims, 40 and 42 respectively, and the bobbin is disposed such that the nearer rim 40 is generally aligned with the middle of the gap 22 and further disposed such that the articles being transported by the endless belts generally pass through and along the axis of rotation of the bobbin. The wrapping material is unreeled from the bobbin by passing it through a tensioning and guiding device shown generally at 44 which is frictionally engaged, in a manner described subsequently in greater detail, with the raised edge of rim 40.

The apparatus of FIG. 1 operates in the following manner. The battery plates 24 are laid fiat and end-to-end in spaced apart relationship in the center of endless belt 10 at some remote loading station. They are transported by the endless belt toward the wrapping station at gap 22 and just prior to reaching the gap they pass under idler roller 26 which provides suificient downward force to keep the plates from moving laterally during wrapping. As the leading edge of the first battery plate reaches the wrapping station, the free end of the wrapping material is attached to this leading edge, preferably by some adhesive material. Obviously the wrapping could be initiated by momentarily holding the free end of the wrapping material onto the plate for a few wraps and then releasing it, at which time it becomes self-holding so that it does not unravel from the plate. As the apertured bobbin is rotationally driven by driving means 38 and 36 about its axis, through which the battery plate is passing at a speed selected according to the desired number of wraps per inch and in synchronism with the velocity of the endless belts, the strand of wrapping material 32 is drawn through the tensioning device 44 and is continuously wrapped around the battery plate as :the latter advances. As the battery plate passes over the gap into contact with endless belt 12, roller 28 secures it to the latter belt so as to continue its progression through the wrapping station toward a receiving end in the direction of arrow 16. The particular battery plate configuration illustrated in FIG. l is one in which along the trailing edge there is a small extension and, if necessary, the wrapping will be continued around said extension since the tensioning device 44 is such that it will provide the proper amount of wrapping material at the required tension.

As will be subsequently described in greater detail, the forces acting on the wrapping material in passing through the tensioning device are imparted to the latter in a manner such as to cause the latter to compensate for any substantial change in tension thereby retaining a relatively constant tension on and supply of the wrapping material. As the trailing edge of the first-in-line battery plate passes the wrapping station at gap 22, the wrapping material may be severed thereby removing any tension on it. The tensioning device 44 then operates to prevent any further unreeling of the wrapping material from the bobbin until the next battery plate is brought into the Wrapping station. Preferably the battery plates on the belt are in juxtaposition end-to-end so that the wrapping can continue from one to the next without interruption and then the plates can be subsequently separated by severing the extension of the wrapping material between successive plates.

Details of the embodiment of the tensioning device 44 utilized in the machine described in FIG. 1 are shown in FIG. 2. Preferably, the device is formed from a single length of 18-8 stainless steel spring Wire. The wire is bent into a pair of generally inverted U-shaped clips 46 and 48 respectively, which are connected together by a single turn loop or eyelet 50 formed from the wire extending between one arm of each of the clips. A length of the wire is further extended from the other arm of clip 48 in a general downward direction and curved back toward clip 46 and at its end is bent inwardly forming the foot 54 of an elongated, curved L 52. In order to illustrate more clearly the engagement and relative placement of the various portions of the tensioning device, phantom dashed lines indicating a portion of the raised nm 40 and the annular opening of bobbin 30 are included and are respectively designated at 56 and 58. Arrow 60 shows the direction of travel of the bobbin when revolving and the strand of wrapping material, 62, is shown passing through eyelet 50.

Clips 46 and 48 are slipped over the raised edge 56 of rim 40 into frictional engagement therewith and are displaced from one another along the line of travel of said edge with eyelet 50 disposed therebetween at a level above the raised edge. The eyelet and the arms of. the respective U-shaped clips to which it is attached are disposed along the inner surface of rim 40. The curved, elongated L- structure 52 extending from the other arm of clip 48 passes along the outer surface of the rim and is yieldingly biased such that foot 54 is frictionally engaged with the annular surface 58 so as to prevent the clips from slipping upwardly out of engagement with the rim of the bobbin. It should be noted that the length of the curved extension 52 from the point where clip 48 is resting on the raised edge 56 to the foot 54 is greater than the radial distance between the annular surface 58 and the raised edge 56. As illustrated in FIG. 1, the strand of wrapping material 62 passes from the bobbin through the eyelet 50 and outwardly and downwardly in a radial direction toward the wrapping station.

Consider first the condition when there is no plate in the wrapping station and the end of the wrapping material outside the bobbin is hanging free so that there is no tension on the strand of wrapping material. The tensioning device is then in the condition illustrated in FIG. 2 and the degree of frictional engagement of foot 54 and clips 46 and 48 with the bobbin is such that in this condition the tension device will effectively be fixedly attached to the bobbin and travels with the bobbin as it revolves in the direction of arrow 60. The free-hanging length of wrapping material will likewise be carried along the eyelet 50 so that no wrapping material will unreel from the bobbin. Next, consider that the free end is attached to a plate in the wrapping station thereby putting tension on the strand of wrapping material indicating a demand to supply material. The force on the wrapping material is imparted to the guiding eyelet 50 which in turn at least momentarily causes the degree of frictional engagement between the guiding and tensioning device and me bobbin to be reduced. This is briefly explained as follows with reference to FIG. 3. The tensional force on the strand of wrapping material 62 in a radial direction toward the wrapping station, as indicated by arrow 64, is at least in part imparted to the eyelet 50, through which the strand passes, causing it to move radially downward toward the raised edge 56 of rim 40. Since clips 46 and 48, which are attached to eyelet 50, are riding on the raised edge 56, they cannot move radially along with the eyelet. However, there is imparted to the curved L-shaped extension 52 a force having a component in a direction of arrow 60 of sufficient magnitude to overcome, at least momentarily, the bias tending to hold foot 54 against annular surface 58. This is illustrated in FIG. 3 which shows displacement of the foot 54 from the annular surface with eyelet 50 forced downward by the tension on strand 62. There results a decrease in the degree of frictional engagement of the tensioning device with the bobbin allowing the device to slip backwards with respect to the direction of travel of the bobbin to compensate for the increase in tension on the strand of wrapping material. The resulting decrease in tension allows the spring biasing force to dominate so that foot 54 is again directed toward a position of rest against the annular surface. This operation of the tensioning device may be a continuous slippage or may be intermittent as the bobbin revolves but is operative to effect a state of equilibrium between the tension on the strand of wrapping material and the demand to supply material to the wrapping station at the required rate.

Because of the slippage, the tensioning and guiding device will revolve about the wrapping station at a rate less than that of the speed of revolution of the bobbin and the difference is determined by the demand. The tensional force on the wrapping material will always be maintained below the structural limits. If for some reason there should be a sudden substantial increase in the tension on the strand of wrapping material, this would indicate demand for an increased quantity of wrapping material from the bobbin in a relatively short period of time. This sudden increase in tension force is imparted to the eyelet which in turn reduces the degree of frictional engagement of the device with the bobbin to effect sufiicient slippage so that the demand for tape material is met virtually instantaneously. The increased slippage further compensates for the sudden increase in the tension on the wrapping material to prevent any breakage thereof by the tension exceeding the structural limitations of the wrapping material. It can be seen that the incorporation of this type of tensioning and guiding device allows a wrapping machine as illustrated in FIG. 1 to accommodate articles of various sizes and configurations while maintaining the continuous wrapping thereof at a desirable tension and in a uniform pattern by supplying the wrapping material at the desired rate of demand.

In an exemplary case, a battery plate approximately six inches wide and one-quarter inch thick is wrapped using a bobbin in which the radial distance from the axis to the level of wrapping material is eighteen inches. Since the circumferential length of wrapping material is approximately 1l3 inches and one wrap around the plate requires only l2 /z inches, the tensioning device will slip backwards with respect to the bobbin at the average rate of 12 /2 inches per revolution to unreel the wrapping material at the required rate. Obviously there will be greater slippage when the wrapping material is being applied to the width surfaces of the plate than when it is applied to the thickness surfaces, since the demand is greater for the former than for the latter.

It should be understood that the invention is not restricted to the particular means for frictionally engaging the bobbin as described herein although its simplicity and advantageous features are particularly pointed out in this embodiment. Obviously the device could be mounted on the revolving supply member, such as the bobbin illustrated, in a variety of ways under the teachings of this invention provided that the guiding eyelet is disposed with respect to the slipping means in a manner to efiTect the desirable features of this invention. It is further contemplated that the tensioning and guiding device illustrated need not be formed from a single unitary piece of spring wire, although the latter does afford a relatively inexpensive device having the inherent resilient characteristics required for proper operation of the device.

As a particular improvement of the device illustrated, it is contemplated that the tensioning device 44 would ride on an added rim which is parallel to and coextensive with but spaced apart from rim 40. This additional rim would preferably be detachably coupled to the bobbinand the advantage gained is that a greater amount of wrapping material can be initially spooled onto the bob bin since the arms of the tensioning device between eyelet 59 and clips 46 and 4-8 would be located in the gap between the added rim and the bobbin rim 40 so that the initial level of the wrapping material on the bobbin can be up to the edge 56 of rim 40.

I claim:

1. In a machine for wrapping tape or the like around an article wherein the article passes generally along the axis of an annular bobbin while the latter revolves about said axis unreeling the wrapping material and winding it about the article, guide means for the wrapping material comprising: a pair of inverted U-shaped clips for frictionally engaging one peripheral edge of the bobbin, said clips displaced from one another along the line of travel of said edge; an eyelet through which the Wrapping material slidably passes from the bobbin to the wrapping station disposed between and resiliently attached to one extremity of each of said clips; and an elongated L-shaped extension from the other extremity of one of the clips curved in a direction toward the eyelet and yieldingly spring biased so that the foot of the L extension is frictionally engaged with the annular surface in a manner such that tensional force on the wrapping material imparted to the eyelet overrides the bias to cause the foot to disengage from the annular surface.

2. The device as in claim 1 wherein said clips, eyelet and L-shaped extension are formed from a unitary length of spring wire.

3. For use in a wrapping machine wherein an article is wrapped with tape or the like from an annular bobbin revolving about its axis as the article passes along said axis, a tape-tensioning and guiding device, comprising: a unitary piece of spring wire formed into a pair of clips each adapted for frictional engagement with one end of the bobbin, said clips displaced from one another along a line of travel of said one end of the bobbin as the bobbin revolves; and a single turn loop disposed between said the bobbin to the article being wrapped, said loop forming an eyelet in a plane parallel to the plane defined by that part of the bobbin to which the clips are engaged.

4. In a machine for wrapping material around an article wherein the article passes generally along the axis of an annular bobbin containing the wrapping material while the latter revolves about said axis unreeling the wrapping material and winding it about the article, guide means for the wrapping material comprising: a pair of clips for frictionally grasping the raised edge of a single rim at one end of the bobbin, said clips displaced from one another along said rim; an eyelet through which the wrapping material slidably passes from the bobbin to the Wrapping station, said eyelet extending above said raised edge and resiliently attached between one extremity of each of said clips; and a leg extending downward from the other extremity of one of said clips below said rim to be in sliding contact with or disengagement from the annular surface of the bobbin.

5. The device as in claim 4 wherein said clips and said eyelet and said extending leg are formed from a unitary length of spring wire.

6. The invention described in claim 4 wherein the resilient attachment of the eyelet causes the degree of friction between the clips and the bobbin and between said extension and the annular surface of the bobbin to change inversely to the change in tensional force on the wrapping material as it passes through the eyelet.

'7. In a machine for wrapping tape or the like around an article wherein the article passes generally along the axis of an annular bobbin while the latter revolves about said axis unreeling and wrapping material and winding it about the article, guide means for the wrapping material comprising: a pair of clips for frictionally engaging one peripheral edge of the bobbin, said clips displaced from one another along the line of travel of said one edge; an eyelet through which the wrapping material slidably passes from the bobbin to the wrapping station, said eyelet extending beyond said one edge between and resiliently attached to said clips for changing the degree of frictional engagement between the clips and the bobbin inversely as the tension of the wrapping material changes; said clips and said eyelet beingformed from a unitary piece of spring wire, with the clips being at least in part of general U-shape configuration and the eyelet being a single turn coil between one extremity of each of the clips.

8. The device as in claim 7 wherein one of the clips has an extension from the other extremity of the U- shaped portion which is yieldingly biased into frictional engagement with the annular surface of the bobbin.

9. The device as in claim "7 wherein the eyelet is in a plane which is substantially parallel to the plane defined by that part of the bobbin to which the clip means is attached.

References Cited by the Examiner UNITED STATES PATENTS 2,726,817 12/1955 Bar-rows 2424 2,850,247 9/1958 Frederick 242-4 FOREIGN PATENTS 535,153 1/1957 Canada. 308,077 9/1918 Germany. 362,144 7/ 1962 Switzerland.

STANLEY N. GILREATH, Primary Examiner. clips through which the Wrapping material passes from MERVIN STEIN, FRANK J, COHEN, Examiners. B. S. TAYLOR, Assistant Examiner. 

7. IN A MACHINE FOR WRAPPING TAPE OR THE LIKE AROUND AN ARTICLE WHEREIN THE ARTICLE PASSES GENERALLY ALONG THE AXIS OF AN ANNULAR BOBBIN WHILE THE LATTER REVOLVES ABOUT SAID AXIS UNREELING AND WRAPPING MATERIAL AND WINDING IT ABOUT THE ARTICLE, GUIDE MEANS FOR THE WRAPPING MATERIAL COMPRISING: A PAIR OF CLIPS FOR FRICTIONALLY ENGAGING ONE PERIPHERAL EDGE OF THE BOBBIN, SAID CLIP DISPLACED FROM ONE ANOTHR ALONG THE LINE OF TRAVEL OF SAID ONE EDGE; AN EYELET THROUGH WHICH THE WRAPPING MATERIAL SLIDABLY PASSES FROM THE BOBBIN TO THE WRAPPING STATION, SAID EYELET EXTENDING BEYOND SAID ONE EDE BETWEEN AND RESILIENTLY ATTACHED TO SAID CLIP FOR CHANGING THE DEGREE OF FRICTIONAL ENGAGEMENT BETWEEN THE CLIPS AND THE BOBBIN INVERSELY AS THE TENSION OF THE WRAPPING MATERIAL CHANGES; SAID CLIPS AND SAID EYELET BEING FROMED FROM A UNITARY 